In the very interesting and inspiring article [1]} (also [2]}, [3]}), G. Cotti, B. Dubrovin and D. Guzzetti have analyzed with much care the case where \(T\)  parametrizes the eigenvalues of the matrix \(A_0\) , which is then assumed to be the matrix \((t_1,\dots ,t_n)\) , and \(t_o\)  belongs to the union \(\Delta \)  of diagonal hyperplanes (coalescing eigenvalues). In particular, they have shown how Stokes data at \(t_o\)  can be extended in some neighbourhood of \(t_o\) , and they gave applications to Frobenius manifolds.
